1. You are making the assumption that the insurance companies models of what is and is not a risky lifestyle are correct.
2. For the same reason that your employer is not entitled to put cameras in your bathroom to make sure you aren't doing anything that might impact your job performance.
1. All other factors being equal, insurance companies with more accurate statistical models will do better.
2.. Because many employees would choose to not work for such an employer, and this negative impact would outweigh the potential benefit? I haven't seen anything to suggest that people would choose not to be insured by a company that profiles its clients in this way.
2. For the same reason that your employer is not entitled to put cameras in your bathroom to make sure you aren't doing anything that might impact your job performance.